Broadcast ratings dropped sharply Thursday night, which wasn’t great for key episodes of NBC’s The Office and Fox’s Bones.

The Bones spin-off “backdoor pilot” The Finder (11.1 million, 3.2) was down 9 percent from last week’s regular episode. Yet, since its American Idol lead-in (19.6 million, 5.6) fell 13 percent, one could argue Bones retained a slightly larger portion of its lead-in this week.

Over on NBC, The Office (6.8 million, 3.3) dropped 18 percent as Will Ferrell continues as guest star and the show ramps up to Steve Carell’s departure.

The working theory: With the Easter holiday approaching and Spring Break underway, many viewers are traveling and therefore TV viewership is down (one reason why ABC and CBS are staying out of the game and aired repeats last night).

Meanwhile, the second week of ThePaul Reiser Show (3.3 million, 0.9) fell even further, with NBC also airing Community (2.5 million, 1.5), Parks and Recreation (5.1 million, 2.5) and the one-hour 100th episode of 30 Rock (4.6 million, 2.2).